Historical Geology 102
Archean Eon Study Guide


After the "Archean Eon" lecture and readings you should be able to answer and discuss the following questions.

What are the Eons and their correct dates on the Geologic Time Scale?

What are the Eras of the Archean Eon?

Of the entire Earth's history, how much (years and percentage) is found in the Eoarchean?

Very little is known about this period of time. Explain why there is so little information.

What is the significance of zircon grains found in Australia and other locations?

How did continental crust begin to form?

What is the significance of the formation of continental crust during the Eoarchean?

Besides the formation of continental crust, what was the other major event that occurred throughout the Eoarchean?

Of the entire Earth's history, how much (years and percentage) is found in the Late Archean?

Of the entire Earth's history, how much (years and percentage) is found in the entire Archean Eon?

What are the two main types of rocks found in Archean terrains? Describe each kind.

What is the typical sequence of rocks found in a Greenstone Belt?

What is the significance of this sequence?

Two models have been developed to explain the formation of Greenstone Belts. Describe each model.

Which model is believed to be correct?

What was the rate of plate tectonic activity during the Archean? Why?

How old is the oldest fossil evidence?

When is life thought to have first evolved on Earth? Why not before this time?

Where did the first life evolve?

Why did it evolve in that location and not somewhere else?

What kind of organism was the first to evolve?

How was life able to evolve from non-living material?

What are stromatolites, and how do they form?

When did photosynthesis evolve?

What is the significance of photosynthesis?